github composer/composer 2.0.0-alpha2

Not up to date with Composer 2 yet? Check the alpha1 changelog and UPGRADE guide first.

Try it out now and get ready for the upcoming stable release

  • Use composer self-update --preview to try the latest alpha/prerelease version (2.x).
  • Use composer self-update --snapshot to try the latest dev build (2.x).
  • Use composer self-update --stable to go back to stable releases (1.x for now).
  • Use composer self-update --1 in CI/scripts if you want to pin Composer to 1.x until you are ready to migrate, this will ensure you stay on 1.x releases even once a 2.0 stable comes out.


  • Added parallel installation of packages (requires OSX/Linux/WSL, and that unzip is present in PATH)
  • Added optimization of constraints by compiling them to PHP code, which should reduce CPU time of updates
  • Added handling of Ctrl-C on Windows for PHP 7.4+
  • Added better support for default branch names other than master
  • Added --format=summary flag to license command
  • Fixed issue in platform check when requiring ext-zend-opcache
  • Fixed inline aliases issues
  • Fixed git integration issue when signatures are set to be shown by default
latest releases: 2.0.0-RC2, 1.10.15, 1.10.14...
pre-release3 months ago